SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '408f7d77e950d509e4462fdd763dbebcab01415ca04262a0241ff0461f1325bb' 
  AND token = 'VPJUGFIdAxe50ljwgVqsiqH7TyRlfI8OZI2UjSAlmwo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}